This invention relates to copy sheet transport systems, and more particularly, to an improved prefuser vacuum transport for copy sheet transported in a copier/printer.
In copier/printer machines, it is common to transport sheets from the photoreceptor to the fuser by means of a multi-belt vacuum transport. Substantial vacuum pressure is usually desirable to provide adequate control over each sheet. This is especially true in machines where the unfused toner image is on the underside of the sheet and the sheet must be suspended from the underside of the vacuum transport. Other factors such as paper curl, cockle and high stiffness also increase pressure requirements.
While under joint influence of the photoreceptor tack force and the prefuser transport vacuum force, the sheet may transmit forces in the forward or backward direction from the prefuser transport to the photoreceptor due to speed mismatches or motion perturbations between the two. In machines, such as color printers, where motion quality of the photoreceptor is critical, these forces can perturb photoreceptor motion during exposure of a subsequent image affecting image quality and color registration. Thus, it would be an advantage to limit the drive force of the transport such that these disturbances are minimized.